Hi,

My 2000 F-250 has a vibration that you can start to notice as you accelerate past about 34 or 35 mph, reaches a maximum at about 38 mph, then dies off as you continue accelerating past about 42 mph or so. I notice the front left tire 'looks like' is is wearing a tad faster than the others, but I haven't tried measuring tread depth on it yet... the difference is small if indeed there is one. That tire also has wheel weights twice the size of the other wheels. I suspect the tire is a bum one from the factory - not consistently made (BF Goodrich A/T radials, stock size). When the tires get balanced, the shop always says "All your tires were 2 ounces off!"

Other than going in for another balance and tire rotation ... does anyone have an input on what else it could be?

Thanks,
Brian

 

Does the vibration start again around 75MPH?

Does your tire place only put weights on the INSIDE of the rim, and not the outside edge?

I'd also take a look at the ball joints, especially the side you say is wearing funny.

 

from what i've read there is also a TSB that mentions shaking at various speeds (40-45, 70-75) but only on crew cab long bed trucks.

 

Do you feel this vibration in the steering wheel or in the seat or both?

 

Jack up the front end by the frame so that the front axle is freely suspended, then use a 2x4 as a lever under the tire with a second set of eyes watching for movement.

Most likely the ball joints between the axle yoke and the spindle, or steering arm ball joint, or slop in the steering box, or the track bar bushings.

 

Not sure on the 75 mph, since I never drive that fast... but I will try that and see.

Tire weights are on inside and out, no problem.

Ball joints should be good. I had one tie rod replaced, and tightened up the adjustment on the steering gear box and a front end alignment. The shop that replaced the tie rod said ball joints are tight (and are after market ones w/zirk fittings, but no hint on age). I had the shop that did the alignment double check front end looseness, including ball joints ... they said all guten-tight. When I had the brakes done and tires rotated later, I had that THIRD shop take a look at ball joints and front end .... again, "Das ist guten tight!". But they said all tires were off by 2 ounces ... drivability was identical, before and after the rotate and balance work.

Brian

 

Thanks, I'll look into that.....

bd

 

It's not a huge vibration, it's more the kind that makes squeaky things such as glove box doors make a little noise. I'd say seat of pants more than anything, and it gets suddenly quieter when a few mph above or below the magic 38 mph.

bd

 

Please see above ... it sounds like these things are all OK ... but who knows?

I'm going in for my Fall rotate and rebalance soon, maybe tomorrow, and will ask them once again to examine the front end ...joints, steering gear, ball joints.

bd

 

If you don't primarily feel it in the steering wheel, then stop looking at your front end. Look at your rear wheels and tires, or rear suspension. Bent rim, bad tire, tire out of balance, wheel not seated on hub, stuff like that.

 

Thanks again for everyone's feedback. Since last posting, I have now had the tires spin balanced and rotated, and have also researched and found the technical service bulletin that applies to the type of 'vibration' that I notice.

First, balance and rotate helped some. The issue has mostly gone away, but does show up once in awhile, usually after decelerating to 38 or so and hitting cruise control (my anti-ticket from hidden cop technique that keeps my speed from creeping up!).

Second, according to the TSB, the issue can result from just a wee little bit of wheel run-out (wobble) and they recommend tire balancing with special K-something plate to get a more accurate balancing. The TSB also mentions that wheel bearing wear can be a part of the equation. My read on this? I have 178k miles on a 17-yr old truck that spend most of its life on Alaska's roads. I think some of this stuff is par for the course in other words. I personally think that the front end design for these years is partially to blame, especially since Ford didn't use it before these years, and changed away from it right after ... and never looked back. What I am referring to is that this truck has zero degrees cast, zero degrees camber, and a recommended zero degrees toe. This design has side effects ... reduced tendency to return to straight when turning, a tendency to wander as the ball joints and steering gear wear a little, and I suspect ... this 'vibration' issue. I think that with a little camber in particular, that the wheel bearings would have an angle on the pressure that is applied to them that naturally takes slop out of them as they wear, rather than the wheels being straight up and the wheel wobbling in/out on worn bearings. My conclusion is that until things get significantly worse (the issue isn't too bad and many wouldn't even notice it), my best plan of attack is regular rebalancing and rotation ... thank you Les Schwab for doing that for me for free! I'd like this truck to last about another 100k or so .... the approximate number of miles I'll drive before I retire, at which time, I will buy a newer and younger truck and start all over!

Brian

 

There has to be some caster or the wheels wouldn't return to straight, and I know it can be adjusted. Matter of fact,I was going to increase it when I did my balljoints, but I never got around to it afterwards.

 

If you figure it out, I'd be interested in knowing what the solution was. I've been chasing the vibration at speeds for a couple of years now and haven't figured it out. I know there's other guys that have chased it for 10 years and still haven't found it. Been through hubs, ball joints, shocks, u-joints, tie rods, etc, etc. I myself am on a 2nd set of rims thinking it was those. about the only thing I haven't done yet is to send the driveshaft out for rebuild and re-balance. Oh mine is an 03 F350 4x4 SC 8ft bed 5.4L auto.

 

There was a recent thread with a guy who did the same thing, turned out it was the factory alloys had "warped" somehow - improper torquing, too much abuse, who knows, but the rims were no longer "true". Something worth checking. And no amount of balancing will fix that.

 

I might just check that out. I had 20's on it when I bought it and with the snowplow package the rockers came up about mid thigh, I'm not young anymore and didn't want to keep jumping up into the truck so I bought a set of used factory 16", I put new rubber on them and had them balanced but never thought about if they were true or not. I guess I'd have to go to a speed shop to see if they were true or not??